This application proposes to work on the following projects: (1) The mechanism of the stimulatory effect of adding intermediates of the malate-aspartate cycle (i.e. alpha-ketoglutarate, malate, asparatate and glutamate) on glucose formation from lactate, ethanol uptake and urea formation from ammonia will be studied in greater detail using isolated rat liver cells. The specific problem involved here is the regulation of intramitochondrial glutamate metabolism by deamination and transamination. Therefore, ancilliary studies will be made with isolated rat liver mitochondria. (2) The effect of alterations of extramitochondrial ATP/ADP and adenine nucleotide phosphate potential on mitochondrial respiration and intramitochondrial nucleotide levels will be studied in isolated rat liver mitochondria. Companion experiments will be done with isolated liver cells usng a new method for rapid disruption of the cell membrane and collection of mitochondria which avoids metabolic interconversions. The purpose of this study will be to define which factors control the rate of mitochondrial respiration in the tissue and the extent to which regulation of adenine nucleotide translocation across the mitochondrial membrane is involved. (3) Regulation of amino acid transport across the liver plasma membrane and hormonal effects on this process.